Designers of instruction set architectures (ISAs) and processors make power and performance trade-offs. As an example, if a designer chooses an ISA with instructions that deliver higher performance then the power consumption by the processor may be higher, as well. Alternatively, if the designer chooses an ISA with instructions that consume lower power, then the performance may be lower. The power consumption may be tied to the amount of hardware resources of the processor, such as arithmetic logic units (ALUs), cache lines, or registers, used by the instructions during execution. Use of a large amount of such hardware resources may deliver higher performance at the cost of higher power consumption. Alternatively, the use of a small amount of such hardware resources may result in lower power consumption at the cost of lower performance.
Compilers are used to compile high-level code into instructions compatible with the ISA and the processor architecture. The compiled instructions are issued by an instruction scheduler when they are ready to be issued.